TCP - OS Test

This test tracks various statistics pertaining to TCP connections to and from each Linux system.

Target of the test : A Linux Systems Group

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each Linux system

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The nick name of the Linux Systems Group component for which this test is to be configured.

Port

Refers to the port at which the specified host listens to. By default, this is NULL.

Inside View Using

To obtain the 'inside view' of performance of the systems - i.e., to measure the internal performance of the systems - this test uses a light-weight eG VM Agent software deployed on each of the systems. Accordingly, this parameter is by default set to eG VM Agent.

Report By User

This flag is set to No by default. This implies that the Linux systems in environments will always be identified using the system name. In other words, this test will, by default, report measures for every systemname. On the other hand, if you want this test to report the measures for every user on a system, then set this flag to Yes. In such a case, this test will report the measures for every username_on_systemname.

Report Powered OS

By default, this flag is set to Yes, then the 'inside view' tests will report measures for even those Linux systems that do not have any users logged in currently. The systems will be identified by their name and not by the username_on_systemname. On the other hand, if this flag is set to No, then this test will not report measures for those systems to which no users are logged in currently.

Is Cloud VMs?

This flag is set to Yes by default. The value of this flag cannot be changed. This implies that the cloud-based Linux systems in environments will always be identified using the login name of the user. In other words, in cloud environments, this test will, by default, report measures for every username_on_systemname.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability

  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Incoming connections to system

Indicates the connections per second received by the system.

Conns/Sec

A high value can indicate an increase in input load.

Outgoing connections to system

Indicates the connections per second initiated by the system.

Conns/Sec

A high value can indicate that one or more of the applications executing on the guest have started using a number of TCP connections to some other guest or host.

Current connections to system

Indicates the currently established connections.

Number

A sudden increase in the number of connections established on a guest can indicate either an increase in load to one or more of the applications executing on the guest, or that one or more of the applications are experiencing a problem (e.g., a slow down). On Microsoft Linux, the current connections metrics is the total number of TCP connections that are currently in the ESTABLISHED or CLOSE_WAIT states.

Connection drops on system

Indicates the rate of established TCP connections dropped from the TCP listen queue.

Conns/Sec

This value should be 0 for most of the time. Any non-zero value implies that one or more applications on the guest are under overload.

Connection failures on system

Indicates the rate of half open TCP connections dropped from the listen queue.

Conns/Sec

This value should be 0 for most of the time. A prolonged non-zero value can indicate either that the server is under SYN attack or that there is a problem with the network link to the server that is resulting in connections being dropped without completion.